NonLinearSigErr is actually OK

testsuite/tests/ghc-regress/indexed-types/should_fail/NonLinearSigErr.hs

 {-# LANGUAGE TypeFamilies #-}
 
+-- This is actually perfectly ok!
+
 module NonLinearSigErr where
 
 type family E a b

testsuite/tests/ghc-regress/indexed-types/should_fail/NonLinearSigErr.stderr

-
-NonLinearSigErr.hs:6:0:
-    Repeat variable occurrence may not have a kind signature: `a'

testsuite/tests/ghc-regress/indexed-types/should_fail/all.T

@@ -28,7 +28,7 @@ test('TyFamArity2', normal, compile_fail, [''])
 test('TyFamUndec', normal, compile_fail, [''])
 
 test('NotRelaxedExamples', normal, compile_fail, [''])
-test('NonLinearSigErr', normal, compile_fail, [''])
+test('NonLinearSigErr', normal, compile, [''])
 
 test('GADTwrong1', normal, compile_fail, [''])